Invitation to Learn:
This demonstration will help to grab your students' attention and introduce
the activity. To prepare, fill a plastic locking bag with ice cubes (leave it
in a freezer until you are ready to do the demonstration). Fill another plastic
locking bag mostly full of water and zip it closed.

Begin by showing the class the two bags and asking them to predict what will
happen when you stick a sharp pencil into each of the bags. Stick the pencil
into the bag of ice. Ask: “Why didn't anything leak out?” Next hold
the bag of water over a large bowl or bucket and quickly stick the pencil through
both sides. No water should leak out. (You should practice this before class.)
Ask the class to explain why the water didn't leak out. (The plastic shrank
together and sealed the hole around the pencil.)

Make a T-chart or Venn Diagram on the board and have the students list the
properties of the ice on one side and the water on the other side. Remind students
that weight is a property of matter. Ask: “If I took a bag of water and
froze it, would it weigh more before it was frozen of after it was frozen?”
Listen to their answers and explain that today they are going to do an experiment
to discover the correct answer to that question.

Using a permanent marker, label a plastic locking bag with your team identification.

Measure 250 ml of water using a measuring cup. Pour the water into the plastic
locking bag and seal the bag.

Make an estimate of the combined weight of the bag and the water. Record
your estimate.

Weigh the bag and the water and record the weight. Compare actual weight
and estimated weight.

Place the bag of water in a freezer.

Record a prediction of what you think the weight of the water and bag will
be after the water has frozen.

Weigh the bag after the water is completely frozen. Record the weight and
compare the frozen weight with the liquid weight.

Write a statement that explains the relationship of the weight of water
and ice.

Predict what the weight of the water will be when it melts. Let the water
melt and check your prediction.

After students have completed the activity allow them to share what they have
learned. Discuss the statement: The weight of a specified quantity of water
(liquid) is equal to the weight of the same quantity of ice (solid). Is this
statement always true? Is freezing a physical change or a chemical reaction?
Why? (No new substance is created; the water just goes through a physical change.)
Is this statement true for all forms of matter? How would you test other types
of matter?

You may wish to allow students to investigate other types of matter. (See Possible
Extensions.)

Extensions:After students have discovered that a specified quantity of water has the same weight, whether frozen or solid, challenge the teams to design an experiment to learn if the same is true for other types of matter. Have the students think of common things that melt and freeze at temperatures that can safely be attained in the classroom. (Many items can be safely melted in the classroom by placing them in a Mason Jar then placing the jar in a pan of water and heating the water on a hot plate. Or, try placing the items on aluminum foil under an adjustable desk lamp.) These items might include chocolate, butter, ice cream, wax, cooking oil, or shortening.

Have each team select a different substance to test and write step-by-step procedures for conducting the experiment. Allow teams to share their data after completing the experiment. Work with each team to ensure that safety concerns are addressed while melting and freezing the substances, and that neat and accurate data is collected.

Assessment Plan:

Use this rubric to assess your students ' performances:

Student 's Name ____________________________________

4

3

2

1

Journal Page

Descriptions and data clear and accurate. All observations
completed.

Descriptions and data mostly clear and accurate. All observations
completed.

Descriptions and data somewhat clear and accurate. All obervations
incomplete.

Descriptions and data unclear and inaccurate. All observations
incomplete.

Participation in
Activity

Used time well and focused attention on the activity.

Used time fairly well. Stayed focused on the activity most
of the time.

Did the activity but did not appear very interested. Focus
was lost on several occasions.

Participation was minimal OR student seemed negative about
participating.

Bibliography:
This lesson is part of the Fifth Grade Science Teacher Resource Book (TRB3) http://www.usoe.org/curr/science/core/5th/TRB5/. The TRB3 is designed to be your textbook in teaching science curriculum to your students. This book covers all the objectives of each standard and benchmark. If taught efficiently, a student should do well on the End-of-Level (CRT) tests. The TRB3 is designed for teachers who know very little about science, as well as for teachers who have a broad understanding of science.